/**
* jQuery upload v1.2
* http://www.ponxu.com
*
* @author xwz
*/
(function($) {
var noop = function(){ return true; };
var frameCount = 0;

$.uploadDefault = {
url: '',
fileName: 'filedata',
dataType: 'json',
params: {},
onSend: noop,
onComplate: noop
};

$.upload = function(options) {
var opts = $.extend(jQuery.uploadDefault, options);
if (opts.url == '') {
return;
}

var canSend = opts.onSend();
if (!canSend) {
return;
}

var frameName = 'upload_frame_' + (frameCount++);
var iframe = $('<iframe style="position:absolute;top:-9999px" />').attr('name', frameName);
var form = $('<form method="post" style="display:none;" enctype="multipart/form-data" />').attr('name', 'form_' + frameName);
form.attr("target", frameName).attr('action', opts.url);

// form中增加数据域
var formHtml = '<input type="file" name="' + opts.fileName + '" onchange="onChooseFile(this)">';
for (key in opts.params) {
formHtml += '<input type="hidden" name="' + key + '" value="' + opts.params[key] + '">';
}
form.append(formHtml);

iframe.appendTo("body");
form.appendTo("body");

// iframe 在提交完成之后
iframe.load(function() {
var contents = $(this).contents().get(0);
var data = $(contents).find('body').html();
if ('json' == opts.dataType) {
data = window.eval('(' + data + ')');
}
opts.onComplate(data);
setTimeout(function() {
iframe.remove();
form.remove();
}, 5000);
});

// 文件框
var fileInput = $('input[type=file][name=' + opts.fileName + ']', form);
fileInput.click();
};
})(jQuery);

// 选中文件, 提交表单(开始上传)
var onChooseFile = function(fileInputDOM) {
var form = $(fileInputDOM).parent();
form.submit();
};